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Biomedical subjects

C Palmer

Publications and source records attributed to C Palmer.

At least 109 records · Page 6Linked to original sources
PubMed1992

The effect of a progesterone/estradiol ear implant on the performance of young beef steers.

A progesterone/estradiol ear implant was tested over a 84 d feedlot period on 96 young Bonsmara steers which were randomly allocated to implant and control groups. Animals were adapted over 5 d to a complete feed formulated to South African feedlot standards. Health aberrations were observed and feed intake, mass gain and slaughter data were recorded. The implant group elicited a 23.2 kg gain per animal (P less than 0.01). Mean treatment feed intakes varied marginally but the implant group showed a 14.91% feed to gain improvement over controls. Warm carcass dressing percentage showed an overall improvement of 4.96% for both groups. Bloat incidence was calculated at 0.98% over 8,064 cattle feedlot days. Mortality was 2.08% and 12 animals were considered to be chronic bloaters. This may have been due to the high proportion of fine particles in the diet. A composite feed sample revealed that 62.48% consisted of particle lengths of 0.5-4mm. The effect of this on ruminal health is briefly discussed. It is concluded that the progesterone/estradiol implant provided greater mass gain and improved feed to gain ratios for treated steers over a control group.

Animal Feed↗
PubMed1991

A follow-up study of colonic epithelial proliferation as a biomarker ina Native-American family with hereditary nonpolyposis colon cancer.

A 7-year follow-up study of colonic mucosa proliferation markers was conducted on members of a Native-American family with hereditary nonpolyposis colon cancer. Reproducibility of a tritiated thymidine autoradiography assay for labeling indexes during this 7-year biologically significant time frame was established. A good correlation between tritiated thymidine and a newer technique, bromodeoxyuridine immunoperoxidase staining, was seen. No confounding effect could be attributed to standard colon preparation. On average, both baseline and follow-up values for epithelial proliferation were within the accepted normal range. The presence of essentially normal labeling indexes among colon cancer patients and their high-risk offspring suggests the possibility of the significant effect of dietary factors in reducing proliferation. Such factors may account for the low risk of colon cancer that characterizes the Native-American population in the American Southwest.

Adult↗
PubMed1991

Acoustic correlates of pathologic voice types.

Listeners classified 49 samples of vowels /a/ and /i/ on the basis of four voice types: hoarse, breathy, strained, and normal. The vowels were analyzed acoustically for mean harmonic/noise differences in four spectral regions, average fundamental frequency, natural logarithm of fundamental frequency, and jitter. Discriminant analysis showed that classifications of voice type were made with 80% accuracy using three acoustic parameters: (a) mean harmonic/noise difference factor (1-3.5 kHz), (b) natural log of fundamental frequency, and (c) vowel type. The significance of these particular acoustic parameters for the perception and classification of voice types is discussed.

Discriminant Analysis↗
PubMed1991

Investigations in the amplitude of sounded piano tones.

The relationship between final hammer velocity and maximum amplitude of radiated piano sound was investigated. Piano tones with varying hammer velocities were produced by a computer-monitored acoustic piano containing optical sensors and solenoids, and the sounded tones were recorded and digitized for analysis. Maximum amplitudes over the duration of the sounded tones were linearly proportional to piano hammer velocities for a range of frequencies and hammer velocities. Changes in room acoustics did not alter the linear relationship. Measurements of maximum amplitudes of individual tones and combined tones (dyads) also indicated a linear relationship between the sum of the maximum amplitudes of the individual tones and the maximum amplitude of the dyads. These findings indicate that the principle of superposition holds for peak amplitudes of sounded piano tones. Findings are discussed with regard to production and perception of musical dynamics.

Computer Graphics↗
PubMed1991

Nutritional support in treatment of oral carcinomas.

Two young adults, one lean and one obese, with squamous cell carcinomas of the oral cavity received aggressive antitumor therapies with comprehensive nutritional support in an effort to minimize the secondary malnutrition that often accompanies cancer treatments.

Adult↗
PubMed1990

Prevalence of trichomoniasis among California beef herds.

Sixty cow-half herds of more than 50 cows each were randomly selected for a prevalence survey of bovine trichomoniasis in California. Herd size, as judged by the number of bulls, ranged from 1 to 210 bulls (median = 8; mean = 59 +/- 15.8). Preputial smegma was collected from 729 bulls (median = 6 bulls/herd) and cultured for Tritrichomonas foetus. Of 57 herds from which samples were collected, 9 (15.8%) had at least one infected bull. Of the 729 bulls from which samples were cultured, 30 (4.1%) were infected. Correcting for sensitivity of the diagnostic test yielded a prevalence of 5.0%. Infection rates for bulls greater than 3 years old and less than or equal to 3 years old were 6.7% and 2.0%, respectively (P less than 0.025). Median herd sizes were 14 bulls (range, 6 to 114) for infected herds and 7 (range, 1 to 210) for uninfected herds. These findings suggest that trichomoniasis is common in California beef herds. Because several bulls less than 4 years old were infected, we suggest that control measures stressing replacement of older bulls with younger ones should be combined with diagnostic procedures in those younger replacements, to ensure that they are not already infected.

Age Factors↗
PubMed1990

Inhibition of the promotional phase of azoxymethane-induced colon carcinogenesis in the F344 rat by calcium lactate: effect of simulating two human nutrient density levels.

The effects of 2 levels of dietary calcium and 2 types of dietary fat on the promotional phase phase of azoxymethane-induced colon cancer in the F344 rat were investigated. During the initiation phase of carcinogenesis all animals were fed a 5% corn oil AIN-76A diet containing 0.32% Ca in the form of calcium lactate. Rats were then injected with azoxymethane (AOM) weekly for 8 weeks. Thereafter, the rats were fed 1 of 3 diet formulations: a 5% corn oil diet or a 20% corn oil or 20% American Blend oil fat diet, with the level of Ca set at either 0.32% of the diet, a nutrient density simulating a daily human intake of approximately 1700 mg Ca/day, or at 0.04% of the diet, reflecting a human daily intake of approximately 200-250 mg of Ca/day, thus modeling 2 human nutrient density levels for calcium. Measurements of fecal pH during the experiment indicated an acidic adaptation of the large bowel to the lactate anion. Analysis of collected fecal samples showed more total fatty acids to be present in the colon when higher amounts of calcium were consumed. However, results of the tumorigenesis study indicated that calcium lactate fed at the 0.32% level significantly inhibited the development of colonic adenocarcinoma in all dietary groups. Taken together, this investigation supports the hypothesis that calcium supplementation can inhibit colon neoplasia in rats fed a high fat diet; however, under the conditions of this study, the 20% fat level did not significantly promote colon cancer as compared to a 5% fat level.

Animals↗
PubMed1990

Mental representations for musical meter.

Investigations of the psychological representation for musical meter provided evidence for an internalized hierarchy from 3 sources: frequency distributions in musical compositions, goodness-of-fit judgments of temporal patterns in metrical contexts, and memory confusions in discrimination judgments. The frequency with which musical events occurred in different temporal locations differentiates one meter from another and coincides with music-theoretic predictions of accent placement. Goodness-of-fit judgments for events presented in metrical contexts indicated a multileveled hierarchy of relative accent strength, with finer differentiation among hierarchical levels by musically experienced than inexperienced listeners. Memory confusions of temporal patterns in a discrimination task were characterized by the same hierarchy of inferred accent strength. These findings suggest mental representations for structural regularities underlying musical meter that influence perceiving, remembering, and composing music.

Attention↗
PubMed1990

Carbohydrate and energy metabolism during the evolution of hypoxic-ischemic brain damage in the immature rat.

The brain damage that evolves from perinatal cerebral hypoxia-ischemia may involve lingering disturbances in metabolic activity that proceed into the recovery period. To clarify this issue, we determined the carbohydrate and energy status of cerebral tissue using enzymatic, fluorometric techniques in an experimental model of perinatal hypoxic-ischemic brain damage. Seven-day postnatal rats were subjected to unilateral common carotid artery ligation followed by 3 h of hypoxia with 8% oxygen at 37 degrees C. This insult is known to produce tissue injury (selective neuronal necrosis or infarction) predominantly in the cerebral hemisphere ipsilateral to the carotid artery occlusion in 92% of the animals. Rat pups were quick-frozen in liquid nitrogen at 0, 1, 4, 12, 24, or 72 h of recovery; littermate controls underwent neither ligation nor hypoxia. Glucose in both cerebral hemispheres was nearly completely exhausted during hypoxia-ischemia, with concurrent increases in lactate to 10 mmol/kg. During recovery, glucose promptly increased above control values, suggesting an inhibition of glycolytic flux, as documented in the ipsilateral cerebral hemisphere by measurement of glucose utilization (CMRglc) at 24 h. Tissue lactate declined rapidly during recovery but remained slightly elevated in the ipsilateral hemisphere for 12 h. Phosphocreatine (P approximately Cr) and ATP in the ipsilateral cerebral hemisphere were 14 and 26% of control (p less than 0.001) at the end of hypoxia-ischemia; total adenine nucleotides (ATP + ADP + AMP) also were partially depleted (-46%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1990

Reduction of perinatal hypoxic-ischemic brain damage with allopurinol.

Cytotoxic free radicals are generated during cerebral hypoxia-ischemia and reperfusion. We studied the efficacy of allopurinol, a xanthine oxidase inhibitor and free radical scavenger, in reducing posthypoxic-ischemic damage in the developing brain of 7-d-old rat pups. Hypoxic-ischemic injury to the right cerebral hemisphere was produced by ligation of the right common carotid artery followed by 3 h of hypoxia with 8% oxygen. Thirty to 45 min before the hypoxia, the rats received either allopurinol (dose = 130-138 mg/kg) or an equal vol of saline (0.2 mL). Some pups were killed at 42 h of recovery for measurement of cerebral hemispheric water content, whereas others were killed at 30 or more d for neuropathologic examination. A total of 18 allopurinol treated rats had significantly less water content in the right hemisphere (89.07 +/- 0.32%) than 23 saline-treated animals (91.64 +/- 0.25%, mean +/- SEM, p less than 0.0001). Rank scoring of neuropathologic alterations revealed that the allopurinol treated rats were less damaged (p = 0.001). Only two of 13 brains from the allopurinol group suffered infarction compared to 10 of the 14 saline-treated animals. The results indicate that allopurinol reduces both cerebral edema and the extent of perinatal hypoxic-ischemic brain damage.

Allopurinol↗
PubMed1990

Assessing the risk of kernicterus using nuclear magnetic resonance.

Kernicterus is the end result of injury to the central nervous system by bilirubin and other factors. Serum bilirubin levels alone are poor predictors of kernicterus especially in sick preterm infants. We need a rapid noninvasive indicator of neurotoxicity and impending cell injury. Bilirubin first seems to affect neuronal conduction before energy metabolism is impaired. Unchecked, this may lead to failure of ATP synthesis, resulting in the breakdown of all active intracellular processes. It is now possible to measure energy metabolism in vivo and noninvasively by surface coil 31P NMR spectroscopy. Recent animal studies demonstrate perturbations in energy metabolism when hyperbilirubinemia is associated with an open BBB. Perhaps the further developments in NMR spectroscopy and imaging will permit regional assessment of impending or actual bilirubin neurotoxicity and allow us to identify those infants in need of immediate treatment.

Adenosine Triphosphate↗
PubMed1989

Studies of spontaneous proliferation of mononuclear cells in human immunodeficiency virus (HIV-1)-infected individuals.

We evaluated the ability of mononuclear cell populations from 56 hemophiliac subjects, 69 homosexuals, and 32 control subjects to proliferate spontaneously in vitro. Levels of spontaneous proliferation (SP) were not significantly different among homosexuals or hemophiliac subjects when they were grouped as asymptomatic human immunodeficiency virus (HIV) seronegative, asymptomatic seropositive, persistent generalized lymphadenopathy, acquired immunodeficiency syndrome-related complex, or acquired immunodeficiency syndrome groups. There was, however, a stepwise increase in levels of SP corresponding with progression of disease in both patient groups. No correlations were noted between SP and CD8+ cell populations or mitogenic responses in study subjects, but SP correlated inversely to percentages and numbers of CD4+ lymphocytes. Depletion of CD4+ cells from mononuclear cell populations of HIV-infected subjects decreased SP. Thus, in HIV-1-infected subjects, SP increases as HIV-1-related disease progresses and appears to be CD4 dependent.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Mapping musical thought to musical performance.

Expressive timing methods are described that map pianists' musical thoughts to sounded performance. In Experiment 1, 6 pianists performed the same musical excerpt on a computer-monitored keyboard. Each performance contained 3 expressive timing patterns: chord asynchronies, rubato patterns, and overlaps (staccato and legato). Each pattern was strongest in experienced pianists' performances and decreased when pianists attempted to play unmusically. In Experiment 2 pianists performed another musical excerpt and notated their musical intentions on an unedited score. The notated interpretations correlated with the presence of the 3 methods: The notated melody preceded other events in chords (chord asynchrony); events notated as phase boundaries showed greatest tempo changes (rubato); and the notated melody showed most consistent amount of overlap between adjacent events (staccato and legato). These results suggest that the mapping of musical thought to musical action is rule-governed, and the same rules produce different interpretations.

Adult↗
PubMed1989

Regional cerebral blood flow and glucose utilization during hypothermia in newborn dogs.

To ascertain the effect of profound hypothermia on brain function and metabolism, newborn dogs were subjected to surface cooling during which regional cerebral blood flow (rCBF) and glucose utilization (rCGU) were measured with iodo-[14C]-antipyrine and 2-deoxy-[14C]-glucose, respectively. Puppies were anesthetized with nitrous oxide, paralyzed, and their lungs artificially ventilated to maintain arterial normoxia (PaO2 greater than 60 mmHg) and normal acid-base balance (PaCO2 = 35-41 mmHg; pHa = 7.34-7.42). When rectal temperature was decreased from 37 to 20 degrees C, mean arterial blood pressure (MABP) decreased from 75 to 47 mmHg (P less than 0.001) and heart rate from 238 to 64 beats/min (P less than 0.001). Arterial PCO2 was reduced from 38 to 31 mmHg (P less than 0.001) (corrected to 37 degrees C), whereas pHa was unchanged from control (7.40). The electroencephalogram slowed progressively and became isoelectric at 22-25 degrees C. During normothermia (n = 6) blood flow to 16 component structures of brain varied from 17 (occipital white matter) to 65 (medulla) ml.100 g-1.min-1, whereas during hypothermia (n = 6) blood flow was lower in all regions (P less than 0.001) at remarkably uniform levels 8.3-10.3 ml.100 g-1.min-1). Thus, the greatest reductions (range, 16-48% of control) in CBF occurred in those structures with the highest intrinsic flows during normothermia and were proportionately less in low flow structures. Regional CGU also decreased in all brain regions analyzed (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Proficiency testing in clinical cytogenetics. The 1986 experience of the College of American Pathologists.

In 1986, the College of American Pathologists introduced a proficiency testing program in cytogenetics entitled "survey CY." Approximately 140 laboratories actively participated. The survey consisted of 20 cytogenetic cases sent to the participants in quarterly shipments of five challenges each. Photographic negatives of metaphases were the primary medium studied. The results reported by the participants were highly concordant for the determination of modal chromosome count and sex chromosome designation. More than 90% of the participants correctly identified the following abnormalities: trisomies 8, 13, 18, 21, and X; monosomy X; t(9;22); t(8;21); der(2) t(2;?); and 5p-. Abnormalities A fra(X)(q27), t(5;11), inv(16), and t(15;17) were correctly identified by more than 80%, 70%, 70%, and 60% of the participants, respectively. The participants had the most difficulty with diagnoses that involved photographs of high-resolution chromosome banding. The 1986 survey was not graded, but the 1987 cytogenetics survey will be scored on those challenges where there is at least 80% consensus among the participants.

Chromosome Aberrations↗